Question

A body moves a distance of $10\, m$ under the action of force $F=10\, N$. If the work done is $25\, J$, the angle which the force makes with the direction of motion is

• A. $0^{\circ}$
• B. $30^{\circ}$
• C. $60^{\circ}$
• D. None of these

Answer 1

Answer: (D)

Work done, $W=F d \cos \theta$
$25=10 \times 10 \cos \theta$
$\cos \theta=\frac{1}{4}$
$\Rightarrow \theta=\cos ^{-1}\left(\frac{1}{4}\right)$